Serotonin syndrome is a rare occurrence, plus at the doses that you are taking, unlikely occurrence.
Paroxetine is particularly good molecule belonging to SSRI group for anxiety as well as depression, but slightly more anxiolytic effect given its receptor binding profile in brain.
Desvenlafaxine is a molecule belonging to SNRI, a very good molecule for treating depression primarily, also has anxiolytic effect, though milder than paroxetine.
Both are wonderful molecules.
Next Steps
In case of any symptoms that you may experience secondary to taking these medications , you should consult a psychiatrist as many of them would be a normal dose related side effect that wanes over time.